How to drive an injector

[JustCallMeOrlando]

Indeed. I would've thought a similar style of injector is likely to have similar electrical characteristics. The nozzles are just bigger.

[JustCallMeOrlando]

Besides. No one should be running bigger injectors on a factory ECU.

[o_man_ra23]

John is right, the injectors dont suck more electricity, they just have bigger holes for the fuel to go through. People blow up ECUs when they use too low of an impedance on their injectors.

Cheers, Owen

[mic*]

Not knowing much bout em, I thought they might just have a bigger nozzle, but then thought that it still wiouldn surprise me if it took more current to drive a bigger nozzle...

Anyway thanx for all the input guys. For $70 i think you cant go wrong with the Jaycar unit. My biggest problem is patience. No-one stocks Jaycar gear do they? Its all mail/net order isn it?

[mrk7]

^^^^Hmmm, for my 4AGTE I was planning to run 4AGZE injectors off stock bigport or smallport ecu. I believe ZE injectors are low impedence like bigport injectors but that the small port are high. So does that mean the smallport computer won't like running ZE injectors?

Am also considering just running another injector off of a Jaycar digital pulse adjuster.

[o_man_ra23]

^^^^Hmmm, for my 4AGTE I was planning to run 4AGZE injectors off stock bigport or smallport ecu. I believe ZE injectors are low impedence like bigport injectors but that the small port are high. So does that mean the smallport computer won't like running ZE injectors?

Am also considering just running another injector off of a Jaycar digital pulse adjuster.

The higher the impedance the lower the current required to drive it. So long as they run the same voltage, then a low impedance ECU can drive high impedance injectors, but not vica versa. HOWEVER often low impedance injectors have external resistor packs (see early ones like 18RGEU), where as high impedance dont have that external resistance. You need to make sure that the overall impedance of the new injectors is no LOWER than the overall impedance of the original injectors.

Cheers, Owen

[JustCallMeOrlando]

Anyway thanx for all the input guys. For $70 i think you cant go wrong with the Jaycar unit. My biggest problem is patience. No-one stocks Jaycar gear do they? Its all mail/net order isn it?

A Jaycar store stocks Jaycar gear

[The Witzl]

^^^^Hmmm, for my 4AGTE I was planning to run 4AGZE injectors off stock bigport or smallport ecu. I believe ZE injectors are low impedence like bigport injectors but that the small port are high. So does that mean the smallport computer won't like running ZE injectors?

Am also considering just running another injector off of a Jaycar digital pulse adjuster.

ALL GZE injectors are low impedance. Just make sure you keep the resistor pack from the factory setup

[The Witzl]

A Jaycar store stocks Jaycar gear

WOW~!!!!1111one

[jonra23]

Where abouts in Queesland are you mic, 2 jaycar stores in Brisbane.
http://www.jaycar.com.au/stores.asp

[The Witzl]

Where abouts in Queesland are you mic, 2 jaycar stores in Brisbane.
http://www.jaycar.com.au/stores.asp

um... 3 stores by my count

- Gabba
- Aspley
- Underwood


and then another in Gold Coast
and another in Townsville

[jonra23]

so i dont count so good

[mic*]

uh. Ta.

[mrk7]

o_man_ra23 - Cheers for that explanation

The Witzl - "Just make sure you keep the resistor pack from the factory setup". Does that mean if I get a smallport engine that I need to keep the smallport resistor pack or the ZE resistor pack?

Cheers

[Mos]

The higher the impedance the lower the current required to drive it. So long as they run the same voltage, then a low impedance ECU can drive high impedance injectors, but not vica versa. HOWEVER often low impedance injectors have external resistor packs (see early ones like 18RGEU), where as high impedance dont have that external resistance. You need to make sure that the overall impedance of the new injectors is no LOWER than the overall impedance of the original injectors.

Only proviso to this is that some Toyota ECUs use peak-and-hold injector drivers for low impedance injectors. This could potential be any low impedance ECU that doesn't run an injector resistor pack. I have only ever seen one (the JDM AE86 4AGE ECU) but that's not to say there aren't others, just that I didn't scope the injector outputs and measure the injector impedance.
The idea is that an injector needs a high current to open, but only a lowish current to remain in the open state, so a peak and hold injector driver first provides a current "peak" (1-2ms iirc) to open the injector and then "holds" a lower current. It is possible that a high impedance injector driven by a peak-and-hold driver will open during the peak, but will shut during the hold time as the current may be insufficient to keep it open.

The opening times of the injector are improved with the high current "peak" over conventional injector drivers that just open and close the injector without changing the current during the open state. As has been stated a few times already a high impedance injector, and a low impedance injector with a resistor pack, is effectively the same thing.
A discussion (years ago) about injector opening times ended in the conclusion that for some reason there must be no actual benefit from peak-and-hold drivers over conventional, as toyota (ND) seemed to have moved completely away from peak and hold. What do aftermarket ECUs use?

Thoughts anyone?

Mos.